1. Field of the Invention
The present invention relates to a method for treating a number of different waste streams in a care institution, such as a hospital, home for the elderly, nursing home and the like. The invention also relates to a system for treating a number of different waste streams in a care institution.
2. Description of the Related Art
Such waste streams may comprise many different kinds of materials. The most elementary are urine and feces which are collected in chamber pots and urinals. It is customary to deposit the urine and feces in a toilet bowl and dispose of them via the public sewage system, following which these will be discharged to the surface water, optionally after purification treatment in a purification installation for public sewage water (RWZI). This has the drawback that the chamber pots and urinals have to be cleaned separately, which is expensive and labor-intensive and, in addition, increases the risk of contamination. A second drawback is the fact that any medicinal and/or toxic substances contained in the urine and/or feces may end up in the surface water.
In order to overcome the first drawback, American document U.S. Pat. No. 6,351,858 B1 discloses a process to collect feces and urine in containers and to gather these containers together with their content. The containers are placed on a trolley and taken to a comminuting machine. The comminuting machine then comminutes the containers (together with their contents) with the addition of a homogenizing liquid, such as water. The combination is discharged to the public sewage system, optionally after having been filtered. Although the known process may have a positive effect on hygiene in the care institution, the abovementioned second drawback of the possible release of medicinal and/or toxic substances into the environment is not overcome. In addition, the known process still requires the containers to be collected and the collected containers to be physically moved by means of a transport vehicle to a comminuting apparatus which is located inside the building of the care institution.
However, there are more waste streams which have to be treated in a care institution. A further waste stream is formed by kitchen waste. This kitchen waste is generally not contaminated, that is to say does not contain medicinal and/or toxic substances which are harmful to the environment, and can be taken to a dump in garbage bags or to an industrial composting plant in containers for vegetable, fruit and garden waste. Collecting kitchen waste, putting it into garbage bags or into containers for vegetable, fruit and garden waste and transporting the garbage bags to a dump or industrial composting plant using trucks is expensive and labor-intensive.
A further waste stream consists of waste water which originates from departments in the care institution which use water, for example bath and/or shower water or water used in a kitchen, which is normally discharged via the sewage system. However, such bath and/or shower water is often polluted with medicinal and/or toxic substances, which, for example, originate from patients' perspiration moisture. The sewage water which is contaminated in this way can then pass into the environment without having been purified or at least not sufficiently purified.
A further waste stream is formed by waste which is caused by the treatment of patients, such as drugs, bandages, etcetera. Such waste is potentially contaminated, that is to say that the waste contains a relatively high concentration of medicinal, bacterially and virally infectious material and/or toxic substances, and discharging such waste untreated has grave consequences. In the first place, the environment where the waste is dumped suffers badly. If such waste reaches a sewage water purification installation (RWZI), additional measures have to be taken in order to remove this waste. This would mean that the entire volume of waste, also the less polluting components thereof have to be treated, which results in high costs. Therefore, in practice, this waste is not discharged via the sewer system, but is discharged strictly separate from the other waste. Currently, specific hospital waste (SHW), also referred to by Eural code 18 of the European list of waste substances, has to be presented in special containers and disposed of in special incinerators suitable for incinerating hospital waste.
As has been explained above, the care institution produces different waste streams. Some waste streams are discharged via the usual sewage system and other waste streams are collected separately and discharged via separate procedures.